The present invention relates to a check valve for shutting off the reverse flow of fluid through a conduit upon a fluid flow reversal event.
A common problem with existing check valves is that upon flow reversal, as can occur in fluid flow systems, the check valve slams shut. The slamming action of the valve and repeated slamming can damage the valve and prevent the valve from operating properly. A need exists for a check valve that can stop the reverse flow of fluid through a fluid carrying conduit without causing damage to the valve or to the conduit. It would be desirable to provide a check valve that does not slam shut upon reverse flow conditions in a fluid carrying conduit but instead is provided with a dampening feature to allow a smooth and non-damaging closing movement of the valve upon reverse fluid flow.
The present invention provides a check valve for allowing the flow of fluid through a fluid-carrying conduit in a normal, forward direction, and for preventing the reverse flow of fluid in a reverse direction. The check valve of the present invention is designed such that upon a reversal of fluid flow through a conduit in which the check valve is employed, the closing movement of the valve is dampened and does not slam shut.
This objective is achieved according to the present invention by providing a check valve that includes a sealing device, a guide plate, and a valve plate with a dampening chamber wherein the sealing device includes a sealing plate, a guide shaft, and a dampening shaft that cooperates with the dampening chamber. The sealing plate is adapted to seal one or more through-passages in the valve plate that allow the flow of fluid through the valve plate. The guide shaft extends from a first surface of the sealing plate and is adapted for reciprocating guided movement within a guide aperture of the guide plate. The guide plate is adapted to be positioned within a fluid-carrying conduit and has one or more through-passages for allowing the flow of fluid through the guide plate. Preferably, the guide aperture is centrally located through the guide plate and guides the reciprocating movement of the guide shaft. The dampening shaft extends from a second surface of the sealing plate that is opposite the first surface. The dampening shaft is adapted for reciprocating movement within the dampening chamber of the valve plate.
The valve plate is adapted to be positioned within a fluid-carrying conduit and has one or more through-passages for allowing the flow of fluid through the valve plate. A seat is provided surrounding the through-passages of the valve plate and is designed for contacting the second surface of the sealing device to prevent the flow of fluid through the through-passages of the valve plate. The dampening chamber receives the dampening shaft and is adapted for providing a fluid cushioning of the dampening shaft as the dampening shaft moves into the dampening chamber, as occurs upon a reversal of fluid flow through the fluid-carrying conduit. At least one of the dampening shaft and the dampening chamber includes a choke bore for preferably allowing the slow escape of compressed fluid from the dampening chamber upon movement of the dampening shaft into the dampening chamber. The dampening shaft, dampening chamber, and choke bore are respectively dimensioned such that when the guide plate, sealing device, and valve plate are operably positioned within a fluid-carrying conduit, and the dampening shaft is forced into the dampening chamber, fluid within the dampening chamber becomes compressed and escapes through the choke bore at a rate that is sufficiently slow to dampen the movement of the dampening shaft into the dampening chamber.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are only intended to provide a further explanation of the present invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate several exemplary embodiments of the present invention and together with description serve to explain the principles of the present invention.